//: io/Blips.java
// Simple use of Externalizable & a pitfall.
package io;

import java.io.*;

import static net.mindview.util.Print.*;

class Blip1 implements Externalizable
{
    public Blip1()
    {
        print("Blip1 Constructor");
    }
    
    public void writeExternal(ObjectOutput out)
        throws IOException
    {
        print("Blip1.writeExternal");
    }
    
    public void readExternal(ObjectInput in)
        throws IOException, ClassNotFoundException
    {
        print("Blip1.readExternal");
    }
}

class Blip2 implements Externalizable
{
    Blip2()
    {
        print("Blip2 Constructor");
    }
    
    public void writeExternal(ObjectOutput out)
        throws IOException
    {
        print("Blip2.writeExternal");
    }
    
    public void readExternal(ObjectInput in)
        throws IOException, ClassNotFoundException
    {
        print("Blip2.readExternal");
    }
}

public class Blips
{
    public static void main(String[] args)
        throws IOException, ClassNotFoundException
    {
        print("Constructing objects:");
        Blip1 b1 = new Blip1();
        Blip2 b2 = new Blip2();
        ObjectOutputStream o = new ObjectOutputStream(new FileOutputStream("Blips.out"));
        print("Saving objects:");
        o.writeObject(b1);
        o.writeObject(b2);
        o.close();
        // Now get them back:
        ObjectInputStream in = new ObjectInputStream(new FileInputStream("Blips.out"));
        print("Recovering b1:");
        b1 = (Blip1)in.readObject();
        // OOPS! Throws an exception:
        // ! print("Recovering b2:");
        // ! b2 = (Blip2)in.readObject();
    }
} /*
   * Output: Constructing objects: Blip1 Constructor Blip2 Constructor Saving objects: Blip1.writeExternal
   * Blip2.writeExternal Recovering b1: Blip1 Constructor Blip1.readExternal
   */// :~
